1. Field of the Invention
The present invention is directed to print heads for use with media printers capable of printing indicia on printable media, and more particularly to a removable print head that includes a memory component capable of storing and/or receiving information.
2. Description of the Related Art
The majority of commonly available printing and copying devices, including media printers capable of printing indicia (such as text, graphics, and the like) on printable media, include an electronic controlling device that, in addition to processing the print data to create the desired indicia, also controls various print parameters of the printing device. For example, commonly available media printers capable of printing indicia on printable media include ink jet and thermal printers that are capable of printing indicia on printable media such as paper, labels, substrates and the like, including lined and linerless media. Print heads for use with these printers are typically removable and replaceable, and thus a single printer may receive several print heads over its lifetime. Additionally, flexibility in media handling provided by commonly available printing and copying devices means that a single printer may be used with a variety of different types of printable media, such as those described above.
In general, thermal printers print indicia on printable media using either direct thermal printing, thermal transfer printing, or both, depending on the type of printable media used in the printer. A thermal print head includes a multitude of printing elements generally disposed in an array across the length of the print head body, perpendicular to the path of the media. The element array may be thermally activated in groups, or each element may be thermally activated individually. Direct thermal printing typically requires media that has a temperature-sensitive surface coating. The printable media is biased against the print head by a backing roller, sometimes referred to as a platen roller. In the case of direct thermal printing, indicia is created on the printable media by heating up an area of the printable media directly beneath the activated elements. The temperature-sensitive coating of the media reacts to the increase in temperature and the indicia is created on the printable media.
A similar print head configuration is generally used with regard to thermal transfer printing, however the printable media used in conjunction with a thermal transfer printer does not typically include a temperature-sensitive surface coating. Instead, thermal transfer printing includes a ribbon containing dye thereon. In such a case, the ribbon is placed between the thermal print head and the printable media. Indicia is created on the printable media by heating up an area of the transfer ribbon beneath the activated elements of the print head. The heat from the print head transfers dye from the ribbon to the printable media.
As noted above, although a single thermal print head may be used for direct thermal printing or for thermal transfer printing, operating parameters relating to the two methods of printing may be different, and such differences may be advantageous in order to provide a user with optimal print performance. For example, the operating temperature of the print head elements, the pressure between the print head and the platen roller, and the feeding rate of the media may be different in order to provide optimal results for the two different methods of thermal printing. Thus, a particular temperature-sensitive ribbon may require a different operating print head temperature than media with a temperature-sensitive coating, and different brands of temperature-sensitive coated media may operate optimally at different print head temperatures.
Moreover, print head information, such as information about the print head itself, or printer information, such as information about the printer, may be advantageous in order to provide a user with optimal print performance. As such, for example, print heads produced by different manufacturers or print heads produced during different production runs may have different performance characteristics. Thus, print head information that identifies the print head, such as various manufacture and identification information, may be useful in order to control printing parameters to optimize print performance when using various print heads. Furthermore, specialized applications often require specialized printing parameters. For example, a printer used in a food processing application, that prints labels from a weigh-scale, is exposed to an exceptionally corrosive environment and may benefit from a printhead incorporating specialized protective coatings that, in turn, require printing parameters different from those of the standard model printhead.
Print heads currently exist that include memory modules for storing various usage and calibration data. For example, U.S. Pat. No. 6,523,926 to Mitsuzawa describes the use of head identification information that is characteristic of the print head so that positional deviation can be avoided during printing. A driver integrated circuit of the print head unit includes a non-volatile memory such as a programmable ROM, for storing the print head identification information. However, many of these prior art print heads include memory modules that utilize read-only memory, do not provide secure memory, and/or require additional communication connections through which the usage and calibration data is transmitted.
Thus, there is a need for an efficient and inexpensive apparatus, system and method for communicating printer and print head information between a printer and a print head. The apparatus, system and method should provide flexibility for the printer and the print head, should provide non-secure and secure memory, and should be capable of storing and receiving a variety of information.